This dissertation is dedicated to:
• My mother, Maria Irene Acuña Cardona, from Chihuahua, Mexico, who taught me the value of frank communication.
• My daughter, Paolina Irene Acuña-González, for trusting my efforts to engage her in open communication and making breakfast so I could write.
• All my family and friends for their love and faith in me.
• All my mentors and students for their guidance and support.
• All urban adolescents and their families for their struggle and heart.
¡Ajúa, we did it, and thank you, Yesus!